<template>
  <el-container class="home-container">
    <!-- 头部区域 -->
  <el-header>
    <div>
      <img src="https://www.mxbc.com/themes/cn/default/assets/images/logo.svg" alt="">
      <span>电商后台管理系统</span>
    </div>
    <el-button type='info' @click="logout">退出</el-button>
  </el-header>
  <!-- 页面主体区域 -->
  <el-container>
    <!-- 侧边栏  -->
    <el-aside :width="isCollapse ? '64px': '200px'">
      <!-- 折叠展开的按钮条 -->
      <div class="toggle-button" @click="toggleCollapse"> ||| </div>
      <!-- 侧边栏菜单区域 -->
      <el-menu 
        background-color="#333744" 
        text-color="#fff" 
        active-text-color="#409EFF" 
        unique-opened :collapse='isCollapse' 
        :collapse-transition="false"
        :router="true"
        :default-active = "activePath"
        >
        <!-- 一级菜单 -->
        <el-submenu :index="item.id + ''" v-for="item in menulist" :key="item.id">
          <!-- 一级菜单的模板区域  -->
          <template slot="title">
            <!-- 图标 -->
            <i :class="iconsObj[item.id]"></i>
            <!-- 文本 -->
            <span>{{ item.authName }}</span>
          </template>
          <!-- 二级菜单 -->
          <el-menu-item :index="'/' + subItem.path" v-for="subItem in item.children" :key="subItem.id" @click="saveNavState('/' + subItem.path)">
            <!-- 图标 -->
            <i class="el-icon-menu"></i>
            <!-- 文本 -->
            <span>{{ subItem.authName }}</span>
          </el-menu-item>
        </el-submenu>
      </el-menu>
    </el-aside>
    <!-- 内容主体 -->
    <el-main>
      <!-- 路由占位符 -->
      <router-view></router-view>
    </el-main>
  </el-container>
 </el-container>
</template>

<script>
export default {
  data() { // 组件的私有数据
    return {
      menulist: [],  // 左侧菜单数据
      // 定义图标的对象 一级菜单id为键, ico图标为值
      iconsObj: {
        '125':'el-icon-user-solid',
        '103':'el-icon-s-help',
        '101':'el-icon-info',
        '102':'el-icon-upload',
        '145':'el-icon-s-fold'
        
      },
      isCollapse : false, // 是否折叠
      activePath : "",    // 被激活的链接地址
    }
  },

  created() { // 生命周期钩子, 调用获取所有左侧菜单函数
    this.getMenuList(),
    this.activePath = window.sessionStorage.getItem('activePath') // 赋值被激活的链接地址
  },

  methods: {
    logout() { // 退出功能 
      window.sessionStorage.clear()     // 清空 token
      this.$router.push("/login")       // 通过编程式导航跳转到后台登录主页
      this.$message.success("退出成功!") // 弹窗提示
    },
    async getMenuList() { // 获取所有的菜单
      const {data: res} = await this.$http.get('menus')
      if(res.meta.status !== 200) return this.$message.error(res.meta.msg)
      this.menulist = res.data
    },
    toggleCollapse() { // 点击按钮切换菜单的折叠与展开
      this.isCollapse = ! this.isCollapse
    },
    saveNavState(activePath) { // 保存链接的激活状态
      window.sessionStorage.setItem('activePath', activePath)
      this.activePath = activePath  // 赋值被激活的链接地址
    }
  }
}
</script>

<style lang="less" scoped>
// 布局容器
.home-container {
  height: 100%;
}
.el-header div img {
  width: 105px;
  height: 50px;
}

// 头部背景色  justify-content: space-between：左右贴边对齐
.el-header {
  background-color: #373d41;
  display: flex;
  justify-content: space-between;
  align-items: center;
  color: #fff;
  font-size: 20px;
  font-family: 幼圆;
  > div {
    display: flex;
    align-items: center;
    span {
      padding: 20px;
    }
  }
}
// 侧边栏背景色
.el-aside {
  background-color: #333744;
  .el-menu  {
    border-right:none;
  }
}

// 主体区域背景色
.el-main {
  background-color: #eaedf1;
}
.toggle-button {
  background-color: #4A5064;
  font-size: 14px;
  line-height: 24px;
  color: #fff;
  text-align: center;
  letter-spacing: 0.02em;
  cursor: pointer;

}
</style>